<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Library of functions specific to course/modedit.php and course API functions.
 * The course API function calling them are course/lib.php:create_module() and update_module().
 * This file has been created has an alternative solution to a full refactor of course/modedit.php
 * in order to create the course API functions.
 *
 * @copyright 2013 Jerome Mouneyrac
 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 * @package core_course
 */

defined('MOODLE_INTERNAL') || die;

require_once($CFG->dirroot.'/course/lib.php');

/**
 * Add course module.
 *
 * The function does not check user capabilities.
 * The function creates course module, module instance, add the module to the correct section.
 * It also trigger common action that need to be done after adding/updating a module.
 *
 * @param object $moduleinfo the moudle data
 * @param object $course the course of the module
 * @param object $mform this is required by an existing hack to deal with files during MODULENAME_add_instance()
 * @return object the updated module info
 */
function add_moduleinfo($moduleinfo, $course, $mform = null) {
    global $DB, $CFG;

    // Attempt to include module library before we make any changes to DB.
    include_modulelib($moduleinfo->modulename);

    $moduleinfo->course = $course->id;
    $moduleinfo = set_moduleinfo_defaults($moduleinfo);

    if (!empty($course->groupmodeforce) or !isset($moduleinfo->groupmode)) {
        $moduleinfo->groupmode = 0; // Do not set groupmode.
    }

    // First add course_module record because we need the context.
    $newcm = new stdClass();
    $newcm->course           = $course->id;
    $newcm->module           = $moduleinfo->module;
    $newcm->instance         = 0; // Not known yet, will be updated later (this is similar to restore code).
    $newcm->visible          = $moduleinfo->visible;
    $newcm->visibleold       = $moduleinfo->visible;
    if (isset($moduleinfo->cmidnumber)) {
        $newcm->idnumber         = $moduleinfo->cmidnumber;
    }
    $newcm->groupmode        = $moduleinfo->groupmode;
    $newcm->groupingid       = $moduleinfo->groupingid;
    $completion = new completion_info($course);
    if ($completion->is_enabled()) {
        $newcm->completion                = $moduleinfo->completion;
        $newcm->completiongradeitemnumber = $moduleinfo->completiongradeitemnumber;
        $newcm->completionview            = $moduleinfo->completionview;
        $newcm->completionexpected        = $moduleinfo->completionexpected;
    }
    if(!empty($CFG->enableavailability)) {
        // This code is used both when submitting the form, which uses a long
        // name to avoid clashes, and by unit test code which uses the real
        // name in the table.
        $newcm->availability = null;
        if (property_exists($moduleinfo, 'availabilityconditionsjson')) {
            if ($moduleinfo->availabilityconditionsjson !== '') {
                $newcm->availability = $moduleinfo->availabilityconditionsjson;
            }
        } else if (property_exists($moduleinfo, 'availability')) {
            $newcm->availability = $moduleinfo->availability;
        }
        // If there is any availability data, verify it.
        if ($newcm->availability) {
            $tree = new \core_availability\tree(json_decode($newcm->availability));
            // Save time and database space by setting null if the only data
            // is an empty tree.
            if ($tree->is_empty()) {
                $newcm->availability = null;
            }
        }
    }
    if (isset($moduleinfo->showdescription)) {
        $newcm->showdescription = $moduleinfo->showdescription;
    } else {
        $newcm->showdescription = 0;
    }

    // From this point we make database changes, so start transaction.
    $transaction = $DB->start_delegated_transaction();

    if (!$moduleinfo->coursemodule = add_course_module($newcm)) {
        print_error('cannotaddcoursemodule');
    }

    if (plugin_supports('mod', $moduleinfo->modulename, FEATURE_MOD_INTRO, true) &&
            isset($moduleinfo->introeditor)) {
        $introeditor = $moduleinfo->introeditor;
        unset($moduleinfo->introeditor);
        $moduleinfo->intro       = $introeditor['text'];
        $moduleinfo->introformat = $introeditor['format'];
    }

    $addinstancefunction    = $moduleinfo->modulename."_add_instance";
    try {
        $returnfromfunc = $addinstancefunction($moduleinfo, $mform);
    } catch (moodle_exception $e) {
        $returnfromfunc = $e;
    }
    if (!$returnfromfunc or !is_number($returnfromfunc)) {
        // Undo everything we can. This is not necessary for databases which
        // support transactions, but improves consistency for other databases.
        $modcontext = context_module::instance($moduleinfo->coursemodule);
        context_helper::delete_instance(CONTEXT_MODULE, $moduleinfo->coursemodule);
        $DB->delete_records('course_modules', array('id'=>$moduleinfo->coursemodule));

        if ($e instanceof moodle_exception) {
            throw $e;
        } else if (!is_number($returnfromfunc)) {
            print_error('invalidfunction', '', course_get_url($course, $moduleinfo->section));
        } else {
            print_error('cannotaddnewmodule', '', course_get_url($course, $moduleinfo->section), $moduleinfo->modulename);
        }
    }

    $moduleinfo->instance = $returnfromfunc;

    $DB->set_field('course_modules', 'instance', $returnfromfunc, array('id'=>$moduleinfo->coursemodule));

    // Update embedded links and save files.
    $modcontext = context_module::instance($moduleinfo->coursemodule);
    if (!empty($introeditor)) {
        $moduleinfo->intro = file_save_draft_area_files($introeditor['itemid'], $modcontext->id,
                                                      'mod_'.$moduleinfo->modulename, 'intro', 0,
                                                      array('subdirs'=>true), $introeditor['text']);
        $DB->set_field($moduleinfo->modulename, 'intro', $moduleinfo->intro, array('id'=>$moduleinfo->instance));
    }

    // Course_modules and course_sections each contain a reference to each other.
    // So we have to update one of them twice.
    $sectionid = course_add_cm_to_section($course, $moduleinfo->coursemodule, $moduleinfo->section);

    // Trigger event based on the action we did.
    // Api create_from_cm expects modname and id property, and we don't want to modify $moduleinfo since we are returning it.
    $eventdata = clone $moduleinfo;
    $eventdata->modname = $eventdata->modulename;
    $eventdata->id = $eventdata->coursemodule;
    $event = \core\event\course_module_created::create_from_cm($eventdata, $modcontext);
    $event->trigger();

    $moduleinfo = edit_module_post_actions($moduleinfo, $course);
    $transaction->allow_commit();

    return $moduleinfo;
}


/**
 * Common create/update module module actions that need to be processed as soon as a module is created/updaded.
 * For example:create grade parent category, add outcomes, rebuild caches, regrade, save plagiarism settings...
 * Please note this api does not trigger events as of MOODLE 2.6. Please trigger events before calling this api.
 *
 * @param object $moduleinfo the module info
 * @param object $course the course of the module
 *
 * @return object moduleinfo update with grading management info
 */
function edit_module_post_actions($moduleinfo, $course) {
    global $CFG;
    require_once($CFG->libdir.'/gradelib.php');

    $modcontext = context_module::instance($moduleinfo->coursemodule);
    $hasgrades = plugin_supports('mod', $moduleinfo->modulename, FEATURE_GRADE_HAS_GRADE, false);
    $hasoutcomes = plugin_supports('mod', $moduleinfo->modulename, FEATURE_GRADE_OUTCOMES, true);

    // Sync idnumber with grade_item.
    if ($hasgrades && $grade_item = grade_item::fetch(array('itemtype'=>'mod', 'itemmodule'=>$moduleinfo->modulename,
                 'iteminstance'=>$moduleinfo->instance, 'itemnumber'=>0, 'courseid'=>$course->id))) {
        if ($grade_item->idnumber != $moduleinfo->cmidnumber) {
            $grade_item->idnumber = $moduleinfo->cmidnumber;
            $grade_item->update();
        }
    }

    if ($hasgrades) {
        $items = grade_item::fetch_all(array('itemtype'=>'mod', 'itemmodule'=>$moduleinfo->modulename,
                                         'iteminstance'=>$moduleinfo->instance, 'courseid'=>$course->id));
    } else {
        $items = array();
    }

    // Create parent category if requested and move to correct parent category.
    if ($items and isset($moduleinfo->gradecat)) {
        if ($moduleinfo->gradecat == -1) {
            $grade_category = new grade_category();
            $grade_category->courseid = $course->id;
            $grade_category->fullname = $moduleinfo->name;
            $grade_category->insert();
            if ($grade_item) {
                $parent = $grade_item->get_parent_category();
                $grade_category->set_parent($parent->id);
            }
            $moduleinfo->gradecat = $grade_category->id;
        }
        $gradecategory = $grade_item->get_parent_category();
        foreach ($items as $itemid=>$unused) {
            $items[$itemid]->set_parent($moduleinfo->gradecat);
            if ($itemid == $grade_item->id) {
                // Use updated grade_item.
                $grade_item = $items[$itemid];
            }
            if (!empty($moduleinfo->add)) {
                if (grade_category::aggregation_uses_aggregationcoef($gradecategory->aggregation)) {
                    if ($gradecategory->aggregation == GRADE_AGGREGATE_WEIGHTED_MEAN) {
                        $grade_item->aggregationcoef = 1;
                    } else {
                        $grade_item->aggregationcoef = 0;
                    }
                    $grade_item->update();
                }
            }
        }
    }

    require_once($CFG->libdir.'/grade/grade_outcome.php');
    // Add outcomes if requested.
    if ($hasoutcomes && $outcomes = grade_outcome::fetch_all_available($course->id)) {
        $grade_items = array();

        // Outcome grade_item.itemnumber start at 1000, there is nothing above outcomes.
        $max_itemnumber = 999;
        if ($items) {
            foreach($items as $item) {
                if ($item->itemnumber > $max_itemnumber) {
                    $max_itemnumber = $item->itemnumber;
                }
            }
        }

        foreach($outcomes as $outcome) {
            $elname = 'outcome_'.$outcome->id;

            if (property_exists($moduleinfo, $elname) and $moduleinfo->$elname) {
                // So we have a request for new outcome grade item?
                if ($items) {
                    $outcomeexists = false;
                    foreach($items as $item) {
                        if ($item->outcomeid == $outcome->id) {
                            $outcomeexists = true;
                            break;
                        }
                    }
                    if ($outcomeexists) {
                        continue;
                    }
                }

                $max_itemnumber++;

                $outcome_item = new grade_item();
                $outcome_item->courseid     = $course->id;
                $outcome_item->itemtype     = 'mod';
                $outcome_item->itemmodule   = $moduleinfo->modulename;
                $outcome_item->iteminstance = $moduleinfo->instance;
                $outcome_item->itemnumber   = $max_itemnumber;
                $outcome_item->itemname     = $outcome->fullname;
                $outcome_item->outcomeid    = $outcome->id;
                $outcome_item->gradetype    = GRADE_TYPE_SCALE;
                $outcome_item->scaleid      = $outcome->scaleid;
                $outcome_item->insert();

                // Move the new outcome into correct category and fix sortorder if needed.
                if ($grade_item) {
                    $outcome_item->set_parent($grade_item->categoryid);
                    $outcome_item->move_after_sortorder($grade_item->sortorder);

                } else if (isset($moduleinfo->gradecat)) {
                    $outcome_item->set_parent($moduleinfo->gradecat);
                }
                $gradecategory = $outcome_item->get_parent_category();
                if ($outcomeexists == false) {
                    if (grade_category::aggregation_uses_aggregationcoef($gradecategory->aggregation)) {
                        if ($gradecategory->aggregation == GRADE_AGGREGATE_WEIGHTED_MEAN) {
                            $outcome_item->aggregationcoef = 1;
                        } else {
                            $outcome_item->aggregationcoef = 0;
                        }
                        $outcome_item->update();
                    }
                }
            }
        }
    }

    if (plugin_supports('mod', $moduleinfo->modulename, FEATURE_ADVANCED_GRADING, false)
            and has_capability('moodle/grade:managegradingforms', $modcontext)) {
        require_once($CFG->dirroot.'/grade/grading/lib.php');
        $gradingman = get_grading_manager($modcontext, 'mod_'.$moduleinfo->modulename);
        $showgradingmanagement = false;
        foreach ($gradingman->get_available_areas() as $areaname => $aretitle) {
            $formfield = 'advancedgradingmethod_'.$areaname;
            if (isset($moduleinfo->{$formfield})) {
                $gradingman->set_area($areaname);
                $methodchanged = $gradingman->set_active_method($moduleinfo->{$formfield});
                if (empty($moduleinfo->{$formfield})) {
                    // Going back to the simple direct grading is not a reason to open the management screen.
                    $methodchanged = false;
                }
                $showgradingmanagement = $showgradingmanagement || $methodchanged;
            }
        }
        // Update grading management information.
        $moduleinfo->gradingman = $gradingman;
        $moduleinfo->showgradingmanagement = $showgradingmanagement;
    }

    rebuild_course_cache($course->id, true);
    if ($hasgrades) {
        grade_regrade_final_grades($course->id);
    }
    require_once($CFG->libdir.'/plagiarismlib.php');
    plagiarism_save_form_elements($moduleinfo);

    return $moduleinfo;
}


/**
 * Set module info default values for the unset module attributs.
 *
 * @param object $moduleinfo the current known data of the module
 * @return object the completed module info
 */
function set_moduleinfo_defaults($moduleinfo) {

    if (empty($moduleinfo->coursemodule)) {
        // Add.
        $cm = null;
        $moduleinfo->instance     = '';
        $moduleinfo->coursemodule = '';
    } else {
        // Update.
        $cm = get_coursemodule_from_id('', $moduleinfo->coursemodule, 0, false, MUST_EXIST);
        $moduleinfo->instance     = $cm->instance;
        $moduleinfo->coursemodule = $cm->id;
    }
    // For safety.
    $moduleinfo->modulename = clean_param($moduleinfo->modulename, PARAM_PLUGIN);

    if (!isset($moduleinfo->groupingid)) {
        $moduleinfo->groupingid = 0;
    }

    if (!isset($moduleinfo->name)) { // Label.
        $moduleinfo->name = $moduleinfo->modulename;
    }

    if (!isset($moduleinfo->completion)) {
        $moduleinfo->completion = COMPLETION_DISABLED;
    }
    if (!isset($moduleinfo->completionview)) {
        $moduleinfo->completionview = COMPLETION_VIEW_NOT_REQUIRED;
    }
    if (!isset($moduleinfo->completionexpected)) {
        $moduleinfo->completionexpected = 0;
    }

    // Convert the 'use grade' checkbox into a grade-item number: 0 if checked, null if not.
    if (isset($moduleinfo->completionusegrade) && $moduleinfo->completionusegrade) {
        $moduleinfo->completiongradeitemnumber = 0;
    } else {
        $moduleinfo->completiongradeitemnumber = null;
    }

    if (!isset($moduleinfo->conditiongradegroup)) {
        $moduleinfo->conditiongradegroup = array();
    }
    if (!isset($moduleinfo->conditionfieldgroup)) {
        $moduleinfo->conditionfieldgroup = array();
    }

    return $moduleinfo;
}

/**
 * Check that the user can add a module. Also returns some information like the module, context and course section info.
 * The fucntion create the course section if it doesn't exist.
 *
 * @param object $course the course of the module
 * @param object $modulename the module name
 * @param object $section the section of the module
 * @return array list containing module, context, course section.
 * @throws moodle_exception if user is not allowed to perform the action or module is not allowed in this course
 */
function can_add_moduleinfo($course, $modulename, $section) {
    global $DB;

    $module = $DB->get_record('modules', array('name'=>$modulename), '*', MUST_EXIST);

    $context = context_course::instance($course->id);
    require_capability('moodle/course:manageactivities', $context);

    course_create_sections_if_missing($course, $section);
    $cw = get_fast_modinfo($course)->get_section_info($section);

    if (!course_allowed_module($course, $module->name)) {
        print_error('moduledisable');
    }

    return array($module, $context, $cw);
}

/**
 * Check if user is allowed to update module info and returns related item/data to the module.
 *
 * @param object $cm course module
 * @return array - list of course module, context, module, moduleinfo, and course section.
 * @throws moodle_exception if user is not allowed to perform the action
 */
function can_update_moduleinfo($cm) {
    global $DB;

    // Check the $USER has the right capability.
    $context = context_module::instance($cm->id);
    require_capability('moodle/course:manageactivities', $context);

    // Check module exists.
    $module = $DB->get_record('modules', array('id'=>$cm->module), '*', MUST_EXIST);

    // Check the moduleinfo exists.
    $data = $DB->get_record($module->name, array('id'=>$cm->instance), '*', MUST_EXIST);

    // Check the course section exists.
    $cw = $DB->get_record('course_sections', array('id'=>$cm->section), '*', MUST_EXIST);

    return array($cm, $context, $module, $data, $cw);
}


/**
 * Update the module info.
 * This function doesn't check the user capabilities. It updates the course module and the module instance.
 * Then execute common action to create/update module process (trigger event, rebuild cache, save plagiarism settings...).
 *
 * @param object $cm course module
 * @param object $moduleinfo module info
 * @param object $course course of the module
 * @param object $mform - the mform is required by some specific module in the function MODULE_update_instance(). This is due to a hack in this function.
 * @return array list of course module and module info.
 */
function update_moduleinfo($cm, $moduleinfo, $course, $mform = null) {
    global $DB, $CFG;

    // Attempt to include module library before we make any changes to DB.
    include_modulelib($moduleinfo->modulename);

    $moduleinfo->course = $course->id;
    $moduleinfo = set_moduleinfo_defaults($moduleinfo);

    if (!empty($course->groupmodeforce) or !isset($moduleinfo->groupmode)) {
        $moduleinfo->groupmode = $cm->groupmode; // Keep original.
    }

    // Update course module first.
    $cm->groupmode = $moduleinfo->groupmode;
    if (isset($moduleinfo->groupingid)) {
        $cm->groupingid = $moduleinfo->groupingid;
    }

    $completion = new completion_info($course);
    if ($completion->is_enabled() && !empty($moduleinfo->completionunlocked)) {
        // Update completion settings.
        $cm->completion                = $moduleinfo->completion;
        $cm->completiongradeitemnumber = $moduleinfo->completiongradeitemnumber;
        $cm->completionview            = $moduleinfo->completionview;
        $cm->completionexpected        = $moduleinfo->completionexpected;
    }
    if (!empty($CFG->enableavailability)) {
        // This code is used both when submitting the form, which uses a long
        // name to avoid clashes, and by unit test code which uses the real
        // name in the table.
        if (property_exists($moduleinfo, 'availabilityconditionsjson')) {
            if ($moduleinfo->availabilityconditionsjson !== '') {
                $cm->availability = $moduleinfo->availabilityconditionsjson;
            } else {
                $cm->availability = null;
            }
        } else if (property_exists($moduleinfo, 'availability')) {
            $cm->availability = $moduleinfo->availability;
        }
        // If there is any availability data, verify it.
        if ($cm->availability) {
            $tree = new \core_availability\tree(json_decode($cm->availability));
            // Save time and database space by setting null if the only data
            // is an empty tree.
            if ($tree->is_empty()) {
                $cm->availability = null;
            }
        }
    }
    if (isset($moduleinfo->showdescription)) {
        $cm->showdescription = $moduleinfo->showdescription;
    } else {
        $cm->showdescription = 0;
    }

    $DB->update_record('course_modules', $cm);

    $modcontext = context_module::instance($moduleinfo->coursemodule);

    // Update embedded links and save files.
    if (plugin_supports('mod', $moduleinfo->modulename, FEATURE_MOD_INTRO, true)) {
        $moduleinfo->intro = file_save_draft_area_files($moduleinfo->introeditor['itemid'], $modcontext->id,
                                                      'mod_'.$moduleinfo->modulename, 'intro', 0,
                                                      array('subdirs'=>true), $moduleinfo->introeditor['text']);
        $moduleinfo->introformat = $moduleinfo->introeditor['format'];
        unset($moduleinfo->introeditor);
    }
    $updateinstancefunction = $moduleinfo->modulename."_update_instance";
    if (!$updateinstancefunction($moduleinfo, $mform)) {
        print_error('cannotupdatemod', '', course_get_url($course, $cw->section), $moduleinfo->modulename);
    }

    // Make sure visibility is set correctly (in particular in calendar).
    if (has_capability('moodle/course:activityvisibility', $modcontext)) {
        set_coursemodule_visible($moduleinfo->coursemodule, $moduleinfo->visible);
    }

    if (isset($moduleinfo->cmidnumber)) { // Label.
        // Set cm idnumber - uniqueness is already verified by form validation.
        set_coursemodule_idnumber($moduleinfo->coursemodule, $moduleinfo->cmidnumber);
    }

    // Now that module is fully updated, also update completion data if required.
    // (this will wipe all user completion data and recalculate it)
    if ($completion->is_enabled() && !empty($moduleinfo->completionunlocked)) {
        $completion->reset_all_state($cm);
    }
    $cm->name = $moduleinfo->name;
    \core\event\course_module_updated::create_from_cm($cm, $modcontext)->trigger();

    $moduleinfo = edit_module_post_actions($moduleinfo, $course);

    return array($cm, $moduleinfo);
}

/**
 * Include once the module lib file.
 *
 * @param string $modulename module name of the lib to include
 * @throws moodle_exception if lib.php file for the module does not exist
 */
function include_modulelib($modulename) {
    global $CFG;
    $modlib = "$CFG->dirroot/mod/$modulename/lib.php";
    if (file_exists($modlib)) {
        include_once($modlib);
    } else {
        throw new moodle_exception('modulemissingcode', '', '', $modlib);
    }
}

